Angioplasty is a procedure used for the treatment of blockages or stenosis in blood vessels, e.g., arteries. Blockages may occur from cholesterol build up on blood vessel walls or due to formation of thrombus. In angioplasty procedures, a dilatation balloon catheter is generally used in an effort to dilate the blood vessel and open up the blockage area. A balloon catheter may be inserted into a blood vessel of a patient using an introducer. The balloon catheter may be inserted through the introducer and advanced through a blood vessel until the distal end of the balloon catheter is at a desired location in the vasculature, e.g., at the site of a blockage or stenosis. A guide wire may be introduced and used to guide the balloon catheter to the desired location. The balloon catheter is advanced over the guide wire until the balloon is properly positioned. Once properly positioned in a blockage or stenosis area, an expandable balloon at the distal end of the balloon catheter may be inflated, e.g., by passing a fluid through an inflation lumen into the balloon. Relatively high pressures may be used to radially expand the balloon and dilate the lumen of the blood vessel and compress the plaque of the blockage or stenosis.
To perform angioplasty procedures, it is desirable for the balloon catheter to have a narrow profile, or relatively small deflated cross-sectional diameter so it is easier to advance the balloon catheter into a stenosis or blockage area. The balloon of the angioplasty catheter is often formed from a very thin polymeric material to provide for a narrower profile. Further, the balloon can be wrapped or folded about the shaft of the catheter into a tightly folded, deflated configuration, which helps to minimize the profile. While balloons are generally capable of developing high pressures under inflation, the balloons are delicate and can be damaged such that the balloon may fail during inflation. For example, the material of the balloons may be susceptible to scratches or other damage, e.g., during shipping and/or handling, which can result in premature balloon failure. Accordingly, it is desirable to protect the balloon from damage until it is used. A protective sheath/sleeve may be applied over the balloon to provide this protection. The protective sheath also helps to maintain the balloon in its tightly folded, low profile configuration during shipping, handling, and storage. Similar background information and more details may be found in U.S. Pat. Nos. 5,893,868 and6,110,146, each of which is incorporated by reference in its entirety into this application.
It may be desirable to coat balloons for use in angioplasty for various purposes. For example, it may be desirable to coat balloons with bioactive agents or drugs. For example, anti-restenosis, anti-coagulant, and/or anti-thrombogenic drugs coated on an angioplasty balloon may help prevent restenosis. These coatings must also be protected (e.g., by a protective sheath). However, some coatings, e.g., drug-coatings, may be slightly adhesive or sticky causing difficulties in removal of a protective sheath from the balloon at the time of use. Protective sheaths and methods that make removal easier are desirable. Further, it is advantageous to protect the bioactive coating so its benefits may be fully realized at the treatment location, e.g., at the location of the blockage or stenosis. However, the bioactive coating may be scraped off or diminished as the balloon is inserted through an introducer, especially if the balloon must be inserted through another device, such as hemostatic valve, e.g., a hemostatic valve in the introducer. For example, the device or hemostatic valve may have edges and a concentration of force may build up at the edges as the balloon is inserted through the device or hemostatic valve, which may cause the bioactive coating to scrape off. Also, the coating can be more easily displaced, if exposed to liquid prior to insertion.
Protective sheaths, systems, assemblies, devices, methods, etc. that address these and other issues are disclosed herein.